package com.cxb.demotest.mqtt_demo;

import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.MqttCallback;
import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;

/**
 * @author Xbao
 * @description 订阅端
 * @date 2022/6/1 10:16
 */
public class SubscribeSample {

  public static void main(String[] args) {

    //EMQ X 默认端口 1883
    String broker = "a162970ab6.iot-mqtts.cn-north-4.myhuaweicloud.com:1883";
    String TOPIC = "$oc/devices/{device_id}/sys/properties/report";
    int qos = 1;
    String clientid = "test_device_1_0_0_2022060107";
    String userName = "test_device_1";
    String passWord = "689964655dd04dc6be364f87416de1a7b5358f04c20883ba625e249cada053e7";
    try {
      // host为主机名，test为clientid即连接MQTT的客户端ID，一般以客户端唯一标识符表示，MemoryPersistence设置clientid的保存形式，默认为以内存保存
      MqttClient client = new MqttClient(broker, clientid, new MemoryPersistence());
      // MQTT的连接设置
      MqttConnectOptions options = new MqttConnectOptions();
      // 设置是否清空session,这里如果设置为false表示服务器会保留客户端的连接记录，这里设置为true表示每次连接到服务器都以新的身份连接
      options.setCleanSession(true);
      // 设置连接的用户名
      options.setUserName(userName);
      // 设置连接的密码
      options.setPassword(passWord.toCharArray());
      // 设置超时时间 单位为秒
      options.setConnectionTimeout(10);
      // 设置会话心跳时间 单位为秒 服务器会每隔1.5*20秒的时间向客户端发送个消息判断客户端是否在线，但这个方法并没有重连的机制
      options.setKeepAliveInterval(20);
      // 设置回调函数
      client.setCallback(new MqttCallback() {

        public void connectionLost(Throwable cause) {
          System.out.println("connectionLost");
        }

        public void messageArrived(String topic, MqttMessage message) {
          System.out.println("======监听到来自[" + topic + "]的消息======");
          System.out.println("message content:"+new String(message.getPayload()));
          System.out.println("============");
        }

        public void deliveryComplete(IMqttDeliveryToken token) {
          System.out.println("deliveryComplete---------"+ token.isComplete());
        }

      });

      // 建立连接
      System.out.println("连接到 broker: " + broker);
      client.connect(options);

      System.out.println("连接成功.");
      //订阅消息
      client.subscribe(TOPIC, qos);
      System.out.println("开始监听" + TOPIC);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

}
